WASHINGTON — NBC has issued a formal apology to more than 100 members of Congress for omitting the words “under God” from the Pledge of Allegiance during a patriotic montage that aired last month.

The letter, signed by Kyle McSlarrow, president of NBC Universal, comes in response to a complaint by 107 members of Congress that a montage shown during coverage of the U.S. Open golf tournament obscured America’s religious heritage.

The montage featured video of schoolchildren saying the pledge alongside images of soldiers and American flags, but did not include the phrase “under God.” It also omitted “one nation” and “indivisible.”

McSlarrow expressed regret over the segment, saying “a serious error in judgment was made by a small group of people. To be absolutely clear, this was not an ideological decision by the company and was not discussed with or approved by any senior NBC official.”

The letter also stressed that action had been taken, noting, “The employees involved have been reprimanded. And we have already implemented a new checks and balances process for pre-produced pieces, ensuring that nothing will go on the air without senior-level approval.”

The letter was addressed to Reps. Randy Forbes, R-Va., and Mike McIntyre D-N.C., who co-chair the Congressional Prayer Caucus, but was also sent to more than 100 other members of Congress.